Two-Way Laser Link over Interplanetary Distance
David E. Smith,1*
Maria T. Zuber,1,2
Xiaoli Sun,1
Gregory A. Neumann,1,2
John F. Cavanaugh,1
Jan F. McGarry,1
Thomas W. Zagwodzki1
Here we report timed observations with subnanosecond precision
of short laser pulses at a distance of nearly 24 million kilometers
between the Mercury Laser Altimeter (MLA) aboard the MESSENGER
(MErcury Surface, Space ENvironment, GEochemistry, and Ranging)
spacecraft and the NASA Goddard Geophysical and Astronomical
Observatory (GGAO). Forty MLA downlink observations and 90 uplink
observations were obtained during observing sessions on 27 and
31 May 2005. Precise standard ground timing allowed a solution
for spacecraft range, range rate, and acceleration, as well
as clock bias. This experiment established a new distance record
for laser detection and accomplished a two-way laser link at
an interplanetary distance.
2 Massachusetts Institute of Technology, Cambridge, MA 02139–4307, USA.
* To whom correspondence should be addressed. E-mail: dsmith{at}tharsis.gsfc.nasa.gov
